The invention relates to chemical compositions that possess the capability of sufficiently dissolving a variety of cured, i.e. substantially crosslinked, difficult to dissolve polymers, such as those containing the silicon oxide backbone, to an extent that the dissolved resin is readily rinsed away.
The effective removal of Silicone and other various cured polymeric materials from hard substrate surfaces has long been a serious problem particularly in the electronic components manufacturing and the aerospace industries. In the electronics industry the difficulty arises, for example, relative to Silicone-based polymers used as conformal coatings, potting compounds on circuit boards, insulating materials, high thermal and process exposed resists and coatings in wafer processing. In the aerospace field, the problem is faced relative to Silicone-based protective coatings applied during metal machining, wire insulation, sealing of fuselage at fixture points, etc. Additionally, a problem may be confronted in the construction industry relative to Silicone waterproofing of rock and masonry, glass edge bead, insulation and the like. It is thus apparent that a need exists for a suitable composition that will easily and effectively dissolve a variety of cured Silicone polymeric substances which heretofore have presented a persistent problem in being effectively dissolved and easily washed away with water.
It has now been discovered, according to the invention, that a composition comprising a blend of chemistries, which will revert, i.e. breakdown, and dissolve fully crosslinked (cured) Silicone polymers can be prepared. Such polymers include various Silicone rubbers consisting primarily of crosslinked polysiloxane monomers and fillers to include RTV (room temperature vulcanizing), HTV (high-temperature vulcanizing), moulding, sealant, surface coating, and other related compounds containing the [xe2x80x94Sixe2x80x94Oxe2x80x94]n straight chain backbone. When the crosslinked Silicone is exposed to the composition of the invention, the polymer will begin to breakdown, allowing the residue to be easily rinsed away. Applications and use of compositions of the invention include the removal of silicone encapsulation in electronics, sealants in aircraft and other uses involving situations where the elimination of insoluble crosslinked (cured) Silicone polymer is desired. Opportunities exist to use the invention in situations where selective removal is needed of a Silicone polymer in the presence of other organic materials. The choice between a hydrophilic or hydrophobic version of the invention offers a valuable tool when material selectivity is important. The removal rates to effect a thorough elimination, i.e. dissolution and washing away of any given polymeric substance, will vary depending upon the formulation used and the type of polymer, i.e. fillers contained, and amount, i.e. thickness present. Heat and agitation can be expected to improve the removal process.